Dec 10, 2018

A mysterious white-colored plume extending some 950 miles (just over 1,500 kilometers) has been spotted on the leeward side of the Arsia Mons volcano on Mars.

Unlike other Martian cloud structures that seem to poof in and out of existence, this one has staying power, with the lengthy plume hovering near Arsia Mons since Sept. 13 and seen as recently as Nov. 12, according to the European Space Agency. The agency’s Mars Express camera has been recording images of the mountainous cloud.

“Montane clouds are very common on Mars, but it was the length of the cloud and its duration that makes it interesting,” said Francois Forget, a senior research scientist at the National Center for Scientific Research (CNRS) in Paris. “Usually, it is more localized to the volcano.” [The 7 Most Mars-Like Places on Earth].